Main Window initialisation

[rno]

Hi,

My gui has 3 buttons for selecting a directory if required, a button for opening data files and a button for saving a text files (all opening a Qfiledialog dialog).

During the main window initialization I want to change the label of the directory selecting button to the application starting directory (code below)

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent), ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    QDir CurrentDir;
    ui->m_Button_Select_Directory->setText(CurrentDir.currentPath());
}

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent), ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    QDir CurrentDir;
    ui->m_Button_Select_Directory->setText(CurrentDir.currentPath());
}

To copy to clipboard, switch view to plain text mode 

The gui starts with the label changed to the gui starting directory.

My problem is when I clicked either the opening or saving files button the directory picking button is reset to its design value.

Clicking on any other buttons/tabs has not effect. Could it be a Qfiledialog problem?

Can someone point out to the possible problem here?

[stampede]

Why do you think that opening a file dialog will change the button label in your custom ui ? It's more probable that you have setText() call somewhere else in your code.

[rno]

Also I noticed that if I change the mainwindow title it is reset to "mainwindow" if I clicked any of the 3 buttons openinf a Qfiledialog dialog.

[FelixB]

then something is wrong with the slot you're calling when clicking the button. you probably re-initialize your gui.

[rno]

Hi,

I have done some test and it is the use of Qfiledialog static functions: getExistingDirectory
getOpenFileName
getSaveFileName

that seems to trigger once a reset of the gui. What's weird is that it happens only once.

the slots seems fine if I remove the call to Qfiledialog static functions getExistingDirectory, getOpenFileName or getSaveFileName nothing happens.

Why do you think that opening a file dialog will change the button label in your custom ui ? It's more probable that you have setText() call somewhere else in your code.

I checked all my settext and none would explain this behaviour. I also noticed that the gui title is rest to "mainwindow"

[FelixB]

show relevant code, please...

[rno]

Hi,

So to avoid confusion and to make it simple I created a simple example with 2 buttons and that's all. The code was first created by QT creator (QT4 gui application) all default settings. Then 2 buttons were added to the gui with qt designer. Finally one slot created in creator using the option "go to slot".

here is main.cpp

#include <QtGui/QApplication>
#include "mainwindow.h"
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}

#include <QtGui/QApplication>
#include "mainwindow.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}

To copy to clipboard, switch view to plain text mode 

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtGui>
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ui->pushButton->setText("I changed the text");
    setWindowTitle("This is the title I would like to be");
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::changeEvent(QEvent *e)
{
    QMainWindow::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        ui->retranslateUi(this);
        break;
    default:
        break;
    }
}
 
void MainWindow::on_pushButton_2_clicked()
{
    QFileDialog mydialog;
    QString fn = mydialog.getOpenFileName(this, tr("Open File"),"/home",tr("Images (*.png *.xpm *.jpg)"));
}

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtGui>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ui->pushButton->setText("I changed the text");
    setWindowTitle("This is the title I would like to be");
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::changeEvent(QEvent *e)
{
    QMainWindow::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        ui->retranslateUi(this);
        break;
    default:
        break;
    }
}

void MainWindow::on_pushButton_2_clicked()
{
    QFileDialog mydialog;
    QString fn = mydialog.getOpenFileName(this, tr("Open File"),"/home",tr("Images (*.png *.xpm *.jpg)"));
}

To copy to clipboard, switch view to plain text mode 

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
 
namespace Ui {
    class MainWindow;
}
 
class MainWindow : public QMainWindow {
    Q_OBJECT
public:
    MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
protected:
    void changeEvent(QEvent *e);
 
private:
    Ui::MainWindow *ui;
 
private slots:
    void on_pushButton_2_clicked();
};
 
#endif // MAINWINDOW_H

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

namespace Ui {
    class MainWindow;
}

class MainWindow : public QMainWindow {
    Q_OBJECT
public:
    MainWindow(QWidget *parent = 0);
    ~MainWindow();

protected:
    void changeEvent(QEvent *e);

private:
    Ui::MainWindow *ui;

private slots:
    void on_pushButton_2_clicked();
};

#endif // MAINWINDOW_H

To copy to clipboard, switch view to plain text mode 

And here is what's happening: when selecting the second button opening a qfiledialogue using static function getopenfilename the label of the first button and the window title are reset (using dynamic qfiledialog does the same as far as I can tell).

Either there is something I am missing due to my lack of knowledge or this is a bug.

[stampede]

Can you prepare and attach compilable example (I mean all needed files, .cpp, .h and .ui) so we can test it ?
edit:
and can you verify that LanguageChange event is not triggered ? I think all strings will be replaced to defaults set in designer if you call ui->retranslateUi(), you should place all setText(), setTitle() etc. code to be called in event handler in case of LanguageChange event.

[rno]

Hi,

Here are the files.

Yes the retranslate is the problem. This is automatically generated by Qt creator wizard and it did not bother me until now.

I am not quite sure yet to understand the way that this language event loop works or the possible benefits for my gui. My gui is intended to a scientific audience who use english as main working/communication language so I would comment out this retranslate command for the time being.

[stampede]

You don't have to comment out anything, just set new strings and window titles in event handler during LanguageChange event:

void MainWindow::changeEvent(QEvent *e)
{
    QMainWindow::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        this->retranslate();
        break;
    default:
        break;
    }
}
 
void MainWindow::retranslate(){
     ui->retranslateUi(this);
     ui->pushButton->setText(tr("I changed the text"));
     setWindowTitle(tr("This is the title I would like to be"));       
}

void MainWindow::changeEvent(QEvent *e)
{
    QMainWindow::changeEvent(e);
    switch (e->type()) {
    case QEvent::LanguageChange:
        this->retranslate();
        break;
    default:
        break;
    }
}

void MainWindow::retranslate(){
     ui->retranslateUi(this);
     ui->pushButton->setText(tr("I changed the text"));
     setWindowTitle(tr("This is the title I would like to be"));       
}

To copy to clipboard, switch view to plain text mode 

In constructor call this->retranslate() and its done.